OLAND(oxygen limited autotrophic nitrification and denitrification) nitrogen removal system was constructed by coupling with oxygen limited nitritation stage and anaerobic ammonium oxidation stage. Ammonia oxidizer, a...OLAND(oxygen limited autotrophic nitrification and denitrification) nitrogen removal system was constructed by coupling with oxygen limited nitritation stage and anaerobic ammonium oxidation stage. Ammonia oxidizer, as a kind of key bacteria in N cycle, plays an important role at the oxygen limited nitritation stage of OLAND nitrogen removal system. In this study, specific amplification of 16S rDNA fragment of ammonia oxidizer by nested PCR, separation of mixed PCR samples by denaturing gradient gel electrophoresis(DGGE), and the quantification of ammonia oxidizer by fluorescence in situ hybridization(FISH) were combined to investigate the shifts of community composition and quantity of ammonia oxidizer of the oxygen limited nitritation stage in OLAND system. It showed that the community composition of ammonia oxidizer changed drastically when dissolved oxygen was decreased gradually, and the dominant ammonia oxidizer of the steady nitrite accumulation stage were completely different from that of the early stage of oxygen limited nitritation identified by DGGE . It was concluded that the Nitrosomonas may be the dominant genus of ammonia oxidizer at the oxygen limited nitritation stage of OLAND system characterized by nested PCR-DGGE and FISH, and the percentage of Nitrosomonas was 72.5% ±0.8% of ammonia oxidizer at the steady nitrite accumulation stage detected by FISH.展开更多
In aerobic wastewater treatment process, low dissolved oxygen (DO) concentration was generally thought to be harmful to aerobic microorganisms, especially to nitrifying microbes. In fact, ammonium could be well conver...In aerobic wastewater treatment process, low dissolved oxygen (DO) concentration was generally thought to be harmful to aerobic microorganisms, especially to nitrifying microbes. In fact, ammonium could be well converted under low DO and low DO condition could obviously lead to energy saving. In recent years, some new phenomena were found in nitrogen removal reactors operated at low DO concentration, such as sludge granulation;short-cut nitrification -denitrification; simultaneous nitrification-denitrification and denitrification by autotrophic nitrifier. These phenomena were valuable because they could give new method or some convenience to nitrogen removal process. Fig 1, Tab 1, Ref展开更多
文摘OLAND(oxygen limited autotrophic nitrification and denitrification) nitrogen removal system was constructed by coupling with oxygen limited nitritation stage and anaerobic ammonium oxidation stage. Ammonia oxidizer, as a kind of key bacteria in N cycle, plays an important role at the oxygen limited nitritation stage of OLAND nitrogen removal system. In this study, specific amplification of 16S rDNA fragment of ammonia oxidizer by nested PCR, separation of mixed PCR samples by denaturing gradient gel electrophoresis(DGGE), and the quantification of ammonia oxidizer by fluorescence in situ hybridization(FISH) were combined to investigate the shifts of community composition and quantity of ammonia oxidizer of the oxygen limited nitritation stage in OLAND system. It showed that the community composition of ammonia oxidizer changed drastically when dissolved oxygen was decreased gradually, and the dominant ammonia oxidizer of the steady nitrite accumulation stage were completely different from that of the early stage of oxygen limited nitritation identified by DGGE . It was concluded that the Nitrosomonas may be the dominant genus of ammonia oxidizer at the oxygen limited nitritation stage of OLAND system characterized by nested PCR-DGGE and FISH, and the percentage of Nitrosomonas was 72.5% ±0.8% of ammonia oxidizer at the steady nitrite accumulation stage detected by FISH.
文摘In aerobic wastewater treatment process, low dissolved oxygen (DO) concentration was generally thought to be harmful to aerobic microorganisms, especially to nitrifying microbes. In fact, ammonium could be well converted under low DO and low DO condition could obviously lead to energy saving. In recent years, some new phenomena were found in nitrogen removal reactors operated at low DO concentration, such as sludge granulation;short-cut nitrification -denitrification; simultaneous nitrification-denitrification and denitrification by autotrophic nitrifier. These phenomena were valuable because they could give new method or some convenience to nitrogen removal process. Fig 1, Tab 1, Ref
